Mirror Neurons

Posted 01.25.05

NOVA scienceNOW

Why do sports fans feel so emotionally invested in the game, reacting almost as if they were part of the game themselves? According to provocative discoveries in brain imaging, inside our heads we constantly "act out" and imitate whatever activity we're observing. As this video reveals, our so-called "mirror neurons" help us understand the actions of others and prime us to imitate what we see.

Transcript

Mirror Neurons

PBS air date: January 25, 2005

ROBERT KRULWICH: Hello again. Gaze into a mirror, and what do
you see? Well, I see my face, of course. But in my face I see moods, I see
shifts of feeling.

We humans are really good at reading faces and bodies. 'Cause if I can look
at you and feel what you're feeling, I can learn from you, connect to you, I
can love you. Empathy is one of our finer traits, and when it happens it
happens so easily, perhaps because—and this is brand new science, this is
just out of the lab—we may have some special circuitry in our brains that
helps us whenever we look at each other.

Ask yourself, "Why do people get so involved, so deeply, deeply involved,
with such anguish, such pain, such nail biting tension over football?"

COMMENTATOR: The Cleveland Browns are gambling on defense.

ROBERT KRULWICH: Why are we such suckers for sports? And it's
not just sports. We can lose it completely at the movies, at video games,
watching a dance. Is there something about humans, humans particularly, that
allows us to connect so deeply when we watch other people—watch them
moving, watch them playing, watch their faces?

Well, as it happens, scientists have an explanation for this strange
ability to connect. It's new.

DANIEL GLASER: It had never been found on a cellular level before.

ROBERT KRULWICH: A set of brain cells, found on either side of
the head, among all the billions of long branching cells in our brain, these
so-called "mirror neurons," have surprising power.

DANIEL GLASER: What we've found is the mechanism that underlies
something which is absolutely fundamental to the way that we see other people
in the world.

ROBERT KRULWICH: And it began entirely by accident, at a
laboratory in the lovely old city of Parma, Italy, where a group of brain
researchers was working with monkeys, and they were testing a
neuron—that's a brain cell—that always fired...made this
sound...

(NEURON FIRING): Clack, clack, clack.

ROBERT KRULWICH: ...whenever the monkey would grab for a
peanut. So the lab had all these peanuts around, and whenever the monkey made
its move...

Then, one day, the monkey was just sitting around, not moving at all, just
sitting, when a human scientist came into the lab. And when that scientist
grasped the peanut? Yeah, the monkey's cell fired.

Now, the monkey hadn't moved, it was the human that had moved, suggesting
that this neuron up here couldn't tell the difference between seeing something
and doing something—seeing and doing were the same—or more
intriguingly, that for this neuron, watching somebody do something is just like
doing it yourself.

The head of the lab, Giacomo Rizzolatti, thought, "Wow!"

GIACOMO RIZZOLATTI (University of Parma): The same neurons, one
neuron, fired, both when the monkey observed something, and when the monkey is
doing something. It is almost unbelievable.

DANIEL GLASER: It was surprising, because this cell, which was involved
with motor planning for the monkey, turned out to be interested in the
movements of other people as well.

ROBERT KRULWICH: Some people call them "monkey see, monkey do"
neurons, but the name that stuck is "mirror neurons," because with them, the
brain seems to mirror the movements it sees.

This accidental discovery got scientists thinking, doing more tests, and
soon it came pretty clear that this is not just a monkey thing, it's a people
thing, too.

We all know that humans learn by looking and copying; that's what infants
do.

First you look...

MOTHER: One, two, three, four.

ROBERT KRULWICH: ...then you do.

DONNA: Ready? Let's see your feet this way.

ROBERT KRULWICH: And once you've watched and copied and
learned a set of moves, you not only have them in your head, if you see
somebody else doing it you can share the experience. They know the moves, you
know the moves, so you can move with them.

DANIEL GLASER: If you can use the years of training that you, yourself,
have done—learning to crawl, then learning to walk, then learning to
eat—this is an incredibly rich set of knowledge that you could apply to
the problem of actually seeing what's going on.

ROBERT KRULWICH: So that's why, when I head down the street
carrying all these packages, not only do people watch, look how they're
watching.

They feel my predicament because they know what it's like to carry heavy
packages. They know all about "carrying." So as they watch me moving they can
feel themselves moving. Their neurons are "mirroring" the action.

These neurons may be the brain's way of translating what we see so we can
relate to the world.

DANIEL GLASER: The mirror system is the way that you tap into...the way
that you harness your own abilities and project them out into the world.

ROBERT KRULWICH: And people are really good at watching and
translating what we see. Like, with just thirteen moving dots—that's all
there are here—you'll have no trouble recognizing these very ordinary
activities. What's more, tests have shown that when a person sees a movie like
this of his own movement, he'll recognize it immediately as his own.

And that's why sports fans tense with the action, and wince, and leap.
'Cause if you know the game...

FOOTBALL FAN 1: Flag! Flag!

FOOTBALL FAN 2: No, no, no flag.

FOOTBALL FAN: No flag.

ROBERT KRULWICH: ...then your neurons are firing as if it's
you playing, giving whole new meaning to the phrase "armchair quarterback."
That's why it's so easy to be a sports fan.

But there is more, suggests U.C.L.A. professor Marco
Iacoboni. He thinks mirror neurons tie us, not just to other people's actions,
but to other people's feelings.

MARCO IACOBONI (University of California, Los Angeles): So the
idea was to try to figure out how the emotional system and this motor system
are connected together.

We're going to go in the scanner and what you're going to do is to...

ROBERT KRULWICH: To demonstrate, he put me into this very
powerful f.M.R.I. brain scanner that can peer into the brain while it's
working.

And he gave me some goggles so he could show me pictures when I was in
there.

MARCO IACOBONI: So you can see here the eyeball of Robert.

ROBERT KRULWICH: And once he had a good view into my
brain...

MARCO IACOBONI: Nice looking brain.

ROBERT KRULWICH: Thank you.

MARCO IACOBONI: Robert, you're not supposed to talk when we scan you,
all right?

ROBERT KRULWICH: Sorry.

Then he said, "Okay, I'm going to show you a bunch of faces. And for each
face, I want you to imitate it."

So I did that. Then he recorded my brain while I moved my facial
muscles.

MARCO IACOBONI: We're going do, right away, another one.

ROBERT KRULWICH: Okay.

Then he said "Okay, same faces, but this time, don't move a muscle, just
look." So I looked.

When we checked the results...

Oh, there's my brain. I've never seen my brain before.

MARCO IACOBONI: This is your mirror area.

ROBERT KRULWICH: Iacoboni says that the part of my brain
that's working when I make a face, the same part gets busy when I see the
face.

Plus, when I was looking at these faces, I remember feeling extra
uncomfortable, kind of bad. But when these faces came on, I felt, I don't know,
I felt better, almost happy. And, in fact, at that moment I was looking at the
happy face, my brain—and this is my brain at that instant—see that
red area here, it shows activity in the "happy" emotional part of my
brain.

And when I was imitating "happy" faces, look. I get an even bigger
response.

This, says Iacoboni, is a consistent result. Mirror neurons, he believes,
can send messages to the limbic, or emotional system in our brains. So it's
possible these neurons help us tune in to each others' feelings. That's
empathy.

MARCO IACOBONI: We strongly believe that that's a unifying mechanism
that allows people to actually connect at a very simple level.

ROBERT KRULWICH: You are saying that there's a place in my
brain, which...whose job it is to live in other people's minds, live in other
people's bodies?

ROBERT KRULWICH: And great actors instinctively know that if
they put feeling and drama into their bodies,...

HELEN HAYES in A FAREWELL TO ARMS: Hold me tight! Don't let me
go!

ROBERT KRULWICH: ...their faces, we will respond.

GARY COOPER in A FAREWELL TO ARMS: You can't die. You're too
brave to die!

DANIEL GLASER: What actors are experts in is using their movements to
inspire feelings in the people watching. These are the experts in the mirror
system.

V.S. RAMACHANDRAN (University of California, San Diego): We are
intensely social creatures. We literally read other people's minds. I don't
mean anything psychic like telepathy, but you can adopt another person's point
of view.

LINDSAY SCHENK (University of California, San Diego): When you
put it together, what do you think it's going to be?

ROBERT KRULWICH: So if mirror neurons help us connect
emotionally, what about people who have trouble with this? Kids like Christian,
who has autism?

LINDSAY SCHENK: Why do you like LEGO®s?

V.S. RAMACHANDRAN: It's been known for some time that children with
autism could be quite intelligent, but have a profound deficit in social
interaction.

ROBERT KRULWICH: Christian can speak and read and write, but
like many kids with autism, he will avoid eye contact, he often misunderstands
questions.

LINDSAY SCHENK: So, Christian, can you tell me what you did in school
today?

CHRISTIAN: Doing well.

LINDSAY SCHENK: You're doing well?

CHRISTIAN: Mmhmm.

ROBERT KRULWICH: Everybody wants to know what exactly causes
this. So Dr. Ramachandran and his graduate student, Lindsay Schenk, designed an
experiment...

LINDSAY SCHENK: So we're going be reading your brainwaves with this cap.

ROBERT KRULWICH: They recorded brainwaves while the kids
opened and closed their hands and while they looked at a movie of somebody
else's hands. For most people, the brainwave looks the same either way, whether
they're doing or seeing. But for the kids with autism, the wave changes,
suggesting, possibly, that autism might have something to do with broken mirror
neurons.

V.S. RAMACHANDRAN: Their brains may indeed be different in that regard,
and they may have deficits in their mirror neuron system. But we don't know
this for sure yet. There needs to be...additional work needs to be done using
brain imaging.

ROBERT KRULWICH: But what we do know, says Ramachandran, is
that healthy human beings are intensely social. More than our cousins, the
monkeys, we invent ways to connect. We invent dances, and handshakes, and games
to play. We eat together. We meet and we talk. We talk a lot.

V.S. RAMACHANDRAN: Everybody's interested in this question: "What makes
humans unique?" What makes us different from the great apes, for example? You
can say humor—we're the laughing biped—language certainly, okay?
But another thing is culture. And a lot of culture comes from imitation,
watching your teachers do something.

ROBERT KRULWICH: And here V.S. Ramachandran makes a big leap.
He has proposed that at a key moment in our evolution, this is his guess, our
mirror neurons got better. And that made all the difference, he says, because
once we humans got better at learning from each other—looking, copying,
teaching—we could do things the other creatures couldn't.

V.S. RAMACHANDRAN: In other words, if you are a bear, and suddenly the
environment turns cold, you need a few million years to develop polar bear type
layers of fat and fur.

ROBERT KRULWICH: It would take many, many, many bear
generations to select for furrier bears. But, says Ramachandran...

V.S. RAMACHANDRAN: If you're a human, you watch your father slaying
another bear and putting on a fur coat, you know, skinning it, using that as a
coat. You watch it, you learn it instantly. Your mirror neurons start firing
away in your brain, and you've performed the same sequence, complicated
sequence. Instead of going through millions of years of evolution, you've done
it in one generation.

ROBERT KRULWICH: And while no one is claiming that mirror
neurons are the key ingredient that makes us different from other creatures,
what these neurons do suggest about us seems almost self-evident. You can see
it any Sunday at a sports bar, that deep in our architecture, down in our
cells, we are built to be together.

DANIEL GLASER: There'd be very little point in having a mirror system if
you lived on your own. There'd be a lot of point in having a digestive system
if you lived on your own. There'd be a good point in having a movement system
if you lived on your own. There'd be a good point in having a visual system if
you lived on your own. But there'd be no point in having a mirror system. The
mirror system is probably the most basic social brain system. It's a brain
system which there's no point in having if you don't want to interact or relate
to other people.

ROBERT KRULWICH: But we do like to interact. And maybe now, as
never before, we will understand why. Okay, now, before we leave this subject,
we've designed a little mirror neuron exercise.

What we're going to do is take a wishbone, an ordinary wishbone, the kind
you break for good luck, and we're going to take it—come on—and
we're going to take it for a stroll. And, if your mirror neurons are working
properly, when you see anything, even a wishbone walking, you know, along, you
won't just watch that bone, you are going to be that bone.

The walking bone was created and designed by artist Arthur Ganson, and
later in the program we will show you a host of Ganson gadgets in glorious
motion.

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Lovelace Brain Mapping Center
Blondies Sports Bar on the East Side NYC
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